PROJECT SUMMARY/ABSTRACT Despite effective implementation of anti-retroviral therapy (ART) programs, individuals in sub-Saharan Africa remain at increased risk for several neoplastic diseases even when HIV-1 viral load is fully suppressed. Comorbidities, immunodeficiency, inadequate diagnosis and treatment access, advanced disease presentation, available treatment modalities, and socio-economic status are factors known to impact cancer survival. Ocular surface squamous neoplasia (OSSN), the most common tumor of the eye, has emerged as a highly prevalent neoplastic manifestation of the HIV epidemic in Zambia. Advanced disease is associated with profound risk for permanent visual impairment, disease progression, and recurrence is common following surgical excision. Because HIV-1 could impact inflammatory drivers of neoplastic growth or form a local tissue reservoir in ocular tissue, our overall goal is to identify factors, such as HPV con-infection, that may differentially associate with the pathogenesis of OSSN in HIV-1 infected individuals. The project hypothesis is that HIV-1 co-infection promotes infection with specific HPV genotypes, which correlates with increased rates of OSSN. To test this concept, the project team will characterize a cohort of Zambian HIV-1 positive and negative OSSN patients with regard to their HIV-1 disease parameters, OSSN histopathological grading, and socio-demographic occupation and medical risk factors. The team will follow characterization of the cohort by an in-depth molecular investigation of the presence of HPV in the various stages of OSSN neoplasia, and any association of HPV co-infection with HIV infection. It will also investigate the etiological role of HPV through quantification of virally-induced tumor markers such as p16, p53 and YAP, as well as characterizing the genomic integration state of HPV in graded OSSN tumors. Finally, the team will genotype all HPVs detected in association with OSSN to determine whether there are specific HPV genotypes that drive OSSN and segregate by grade, or by HIV-1 co-infection. This study will provide an excellent training and capacity-building opportunity for young Zambian cancer researchers while simultaneously illuminating the potential role of HPV in OSSN by revealing both the genotype(s) responsible, and the molecular pathways dysregulated in tumor tissues. The transfer of molecular diagnostic methods and expertise through this study will likely lead to the development of new prognostic and diagnostic markers, including those that impact prevention and treatment of OSSN or other malignancies in Zambia.